U.S. patent number 8,752,772 [Application Number 13/057,108] was granted by the patent office on 2014-06-17 for system for targeted local air humidification.
This patent grant is currently assigned to Airbus Operations GmbH. The grantee listed for this patent is Walter Kulcke, Robert Schreiber, Christian Schumacher, Karin Thudt. Invention is credited to Walter Kulcke, Robert Schreiber, Christian Schumacher, Karin Thudt.
United States Patent |
8,752,772 |
Schumacher , et al. |
June 17, 2014 |
System for targeted local air humidification
Abstract
In order to increase the air humidity in a cabin region of an
aircraft equipped with a plurality of seats, a device includes a
plurality of humidifying units each arranged in spatial association
with a partial number of the seats and a plurality of outlet
openings. The humidifying units are each designed to enrich a
supplied air stream with gaseous water. The outlet openings are
designed to emit the air streams enriched by the humidifying units
into the cabin region, such that a partial number of the outlet
openings each receive one of the enriched air streams. The air
temperature of the enriched air streams is controlled so that the
local temperature in a target region served by the humidifying unit
does not fall below a dew point.
Inventors: |
Schumacher; Christian (Wedel,
DE), Kulcke; Walter (Jork, DE), Thudt;
Karin (Taufkirchen, DE), Schreiber; Robert
(Graefelfing, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Schumacher; Christian
Kulcke; Walter
Thudt; Karin
Schreiber; Robert |
Wedel
Jork
Taufkirchen
Graefelfing |
N/A
N/A
N/A
N/A |
DE
DE
DE
DE |
|
|
Assignee: |
Airbus Operations GmbH
(Hamburg, DE)
|
Family
ID: |
41501144 |
Appl.
No.: |
13/057,108 |
Filed: |
July 30, 2009 |
PCT
Filed: |
July 30, 2009 |
PCT No.: |
PCT/EP2009/005535 |
371(c)(1),(2),(4) Date: |
March 29, 2011 |
PCT
Pub. No.: |
WO2010/015361 |
PCT
Pub. Date: |
February 11, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110180618 A1 |
Jul 28, 2011 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/EP2009/005535 |
Jul 30, 2009 |
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61086209 |
Aug 5, 2008 |
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Foreign Application Priority Data
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Aug 5, 2008 [DE] |
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10 2008 036 425 |
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Current U.S.
Class: |
236/44C;
62/DIG.5; 62/176.6 |
Current CPC
Class: |
B64D
13/00 (20130101); Y02T 50/40 (20130101); Y02T
50/44 (20130101); B64D 2013/0681 (20130101); B64D
2013/0662 (20130101); Y02T 50/56 (20130101); B64D
2013/0655 (20130101); Y02T 50/50 (20130101) |
Current International
Class: |
G05D
22/00 (20060101) |
Field of
Search: |
;236/44A,44C
;62/176.1,176.6,DIG.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2711701 |
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Jul 2009 |
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CA |
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102004024615 |
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Dec 2005 |
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DE |
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102005029226 |
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Dec 2006 |
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DE |
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102006031361 |
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Jan 2008 |
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DE |
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102006041030 |
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Mar 2008 |
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DE |
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102008004695 |
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Jul 2009 |
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DE |
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Other References
European Patent Office, International Search Report, Form
PCT/ISA/210 (4 pgs.), May 6, 2010, and PCT form PCT/ISA/237 (7
pgs.). cited by applicant.
|
Primary Examiner: Norman; Marc
Attorney, Agent or Firm: Wood, Herron & Evans, LLP
Parent Case Text
This application claims priority, under Section 371 and/or as a
continuation under Section 120, to PCT Application No.
PCT/EP2009/005535, filed on Jul. 30, 2009, which claims priority to
German Application No. 10 2008 036 425.8 and also to U.S.
Provisional Application No. 61/086,209, both filed on Aug. 5, 2008.
Claims
The invention claimed is:
1. A device for increasing the air humidity in a cabin region of an
aircraft equipped with a plurality of seats, comprising: a
plurality of humidifying units, each of which is arranged in
spatial association with a partial number of the plurality of seats
defining corresponding target regions for local air humidification
in the cabin region and each of which selectively enriches a
supplied air steam with gaseous water, a plurality of outlet
openings which are designed to emit the air streams enriched with
gaseous water by the humidifying units into the corresponding
target regions of the cabin region, wherein a partial number of the
outlet openings each receives one of the enriched air streams such
that each of the plurality of humidifying units is associated with
a partial number of the outlet openings, a plurality of temperature
sensors, each of which is arranged in associated ones of the target
regions and each of which detects a local temperature in the
associated target region, and a plurality of first control units,
each of which is electrically connected to one of the plurality of
temperature sensors and each of which controls an air temperature
of the enriched air stream so that the detected local temperature
in the target region does not fall below a dew point in the target
region.
2. The device of claim 1, wherein at least some of the humidifying
units are arranged in or on associated ones of the plurality of
seats.
3. The device of claim 1, wherein at least some of the outlet
openings are arranged on associated ones of the plurality of seats
or in a surrounding area accessible to associated ones of the
plurality of seats by convection.
4. The device of claim 1, wherein a partial number of the
humidifying units are each assigned a water reservoir, from which
the humidifying units draw water for enriching the air streams.
5. The device of claim 4, wherein at least some of the water
reservoirs are arranged removably in or on associated ones of the
plurality of seats.
6. The device of claim 1, wherein a partial number of the
humidifying units are each assigned a blower which serves for
generating the air stream supplied to the associated humidifying
unit, wherein at least some of the blowers are each arranged in or
on associated ones of the plurality of seats.
7. The device of claim 1, wherein at least some of the outlet
openings can be individually positioned or individually oriented at
a joint, and wherein a controlled actuator mechanism is provided at
the joint, which allow the position or orientation of at least one
of the outlet openings to adjust automatically to a position of a
backrest of one of the plurality of seats.
8. The device of claim 1, further comprising: at least one heater
configured to heat at least one of the following phases: supplied
air stream, enriched air stream and supplied water.
9. The device of claim 8, further comprising: at least one sensor
that detects at least one of the following variables temperature,
air humidity, flow rate, pressure and oxygen content of at least
one of the following phases: supplied air stream, enriched air
stream, air stream at one of the outlet openings, supplied water
and air in a surrounding area accessible to one of the seats by
convection.
10. The device of claim 9, wherein the first control units are
further designed to compare the at least one detected variable with
at least one preset variable and to counteract deviations by
regulating at least one of the humidifying units or the at least
one heater.
11. The device of claim 10, wherein the first control unit is
configured for data communication with a separate second control
unit, which serves for controlling a global air conditioning system
for air conditioning supply air separate from the enriched air
streams and blown into the entire cabin region, the first control
unit being configured to transmit the at least one detected
variable or the at least one preset variable and configured to
receive from the second control unit measured or desired values
concerning the air conditioning of the supply air and then correct
the at least one preset variable in dependence on the values
received from the second control unit.
12. The device of claim 1, wherein an evaporating section
downstream of the humidifying unit includes heating devices, mixing
fittings, swirling surfaces or separating surfaces, which serve for
dissolving or separating aerosol particles.
13. The device of claim 1, wherein the gaseous water is conveyed in
at least some of the humidifying units through at least one of the
following: a membrane module, a hollow-fiber membrane module; a pad
evaporator; an evaporator electrically heated by trim air or bleed
air, having an evaporator plate; and an ultrasonic evaporator.
14. The device of claim 1, further comprising: at least one oxygen
source and an inlet opening, arranged upstream of at least some of
the humidifying units, for blowing oxygen or oxygen-enriched air
from the oxygen source into the supplied air stream.
15. The device of claim 14, further comprising: at least one
standardized connection for medical oxygen, which is connected to
the at least one oxygen source and mounted on or in the vicinity of
at least a partial number of the plurality of seats.
Description
TECHNICAL FIELD
The invention relates to a device for air humidification in an
aircraft. In particular, the invention relates to a device of
modular construction for targeted local air humidification in a
cabin region of an aircraft.
BACKGROUND
At typical flight altitudes of commercial or transport aircraft,
pressure and temperature are lower than acceptable for a cabin
region. Pressure-controlled cabins with global air conditioning
systems belong to the prior art. By restricting the air
conditioning of the cabin region to temperature adjustment, the air
humidity during the flight can fall to very low values of a few per
cent relative air humidity, for example 3-5%. The comfort of
persons on board who spend quite a long time in this dry
atmospheric environment is considerably reduced, since the low air
humidity is felt to be unpleasant.
Besides the temperature control, known global air conditioning
systems allow a humidification of the entire cabin air, so that a
relative air humidity of, for example, 30-50% is established. As a
result, a more pleasant atmospheric environment can be produced and
thus the comfort on board increased.
An appropriate solution is described in the patent U.S. Pat. No.
5,595,690. There, membrane sheets are proposed for the central
humidification. Since the required exchange area for a centralised
solution is correspondingly large, the flat, extended design has
proved to be disadvantageous on integration in the aircraft.
Furthermore, a humidification of the entire cabin air involves
increased energy expenditure and water tanks of corresponding size,
and thus the proposed solution results in increased flying weight
and fuel consumption of the aircraft. In addition, the membrane
modules dry after the system is switched off, and the contraction
of the membrane as it dries out causes considerable mechanical
stresses on the membrane module frame. Depending on the type of
connection and seal between adjacent sheets of the sheet membrane
module, deformations due to the mechanical stress can cause leakage
of the module.
A further disadvantage of a global or centralised humidification of
the cabin air is the danger of undesired condensation, in
particular in the vicinity of structural parts of the aircraft
which are relatively cold in flight. Corrosion, malfunctions,
weight increase due to water stored in the insulation or reduction
of insulating properties may result from the formation of the
condensate.
Solutions for local humidification are also known, for example,
from laid-open application DE 10 2004 024 615 A1. There, spraying
methods are used for local humidification. As a result, the air
humidity can be increased in a targeted manner in partial regions
of the cabin, without causing condensation on more remote, cooler
insulation and structural parts of the aircraft. The disadvantage,
however, is that owing to the spraying method the water supplied to
an air stream to be humidified is supplied at least largely in
liquid form. As a result, air containing a large number of small
liquid drops, i.e. aerosols, is expelled into the cabin. The liquid
drops entering the cabin region are generally felt by the cabin
occupants to have an adverse effect on comfort. Furthermore, the
danger of transmitting germs in breathing air increases due to the
aerosols.
An object of the present invention is to ensure a high degree of
climatic comfort for is persons on board, while maintaining
efficient and safe flying operation.
SUMMARY OF THE INVENTION
To achieve this object, according to the invention a device for
increasing the air humidity in a cabin region of an aircraft
equipped with a plurality of seats is provided. The device
comprises a plurality of humidifying units which are arranged in
each case in spatial association with in each case a partial number
of the seats and which are in each case designed to enrich a
supplied air stream with gaseous water. The device further
comprises a plurality of outlet openings which are designed to emit
the air streams enriched by the humidifying units into the cabin
region, in each case a partial number of the outlet openings each
receiving one of the enriched air streams.
The term "seat" herein is to be understood generally in the sense
of a place at which to dwell or region to pass through in the cabin
region. For example, the place at which to dwell can include a bar
in a lounge.
As a result of the air streams enriched with gaseous water, aerosol
formation is limited to a degree imperceptible by cabin occupants.
The danger of germ transmission associated with aerosol formation
is minimised. Owing to the large number of humidifying units which
are in each case assigned to a partial number of the seats, a
modular construction of the device is enabled. In particular, the
demand for humidifying units can be adapted to an actual demand.
Associated with this is efficient utilisation of the flying weight
and on-board resources, such as water and energy, and thus also a
reduction of the fuel consumption. Since in each case a partial
number of the outlet openings each receive one of the air streams
enriched by one of the humidifying units, a plurality of subunits
can be autonomously operated, such a parallel operation ensuring
flexibility and reliability.
At least some of the humidifying units can in each case be arranged
in or on one of the seats. This may be advantageous for a variable
design of the interior finish of the cabin, since complex
installation steps for the humidifying units when changing the seat
arrangement are avoided.
Also, at least some of the outlet openings can be arranged on one
of the seats or in a surrounding area accessible to one of the
seats by convection. As a result, efficient use of the humidified
air for increasing comfort can be achieved, while a lower relative
air humidity prevails at more remote components of the aircraft, so
that a danger of condensation can be minimised.
Preferably, in each case a partial number of the humidifying units
are each assigned a water reservoir, from which the humidifying
unit concerned can draw water for enriching its air stream. As a
result of a decentralised water supply, an autonomous or modular
construction of the device for increasing the air humidity also
with regard to the water supply can be achieved.
At least some of the water reservoirs can be arranged in each case
preferably removably in or on one of the seats. As a result, the
flexibility of the modular construction can be advantageously
extended. Furthermore, it is advantageous to embody a removable
water reservoir, for example, as a sterilely filled and/or
disinfectible water bottle. The water filled into the disinfectible
water bottle can be disinfected before filling. As a result,
complex water treatment on board the aircraft can be avoided, and
the danger of spreading germs due to contaminated water can be
minimised. A preferred use of demineralised water can additionally
be an increase of the service life of the humidifying units, since
a deposit, for example of lime, can be considerably lessened and
also maintenance expenditure reduced. Furthermore, as a result of a
local water supply, the connection to an aircraft supply system for
fresh water and where appropriate also drainage can be avoided. In
addition, pumping of quite large amounts of water through the
aircraft can be avoided and an accompanying safety risk eliminated.
Owing to an elevated position of the water reservoir, it is
additionally possible to ensure water conveyance from the water
reservoir to the humidifying unit by gravitational force, so that a
pump can be completely dispensed with.
Furthermore, in each case a partial number of the humidifying units
can each be assigned a blower which serves for generating the air
stream supplied to the humidifying unit concerned. Preferably, at
least some of the blowers are also arranged in each case in or on
one of the seats.
With regard to the outlet openings, at least some of them can
preferably be individually positioned, individually oriented or are
equipped with in particular controlled actuating means, which
adjust the position or orientation of at least one of the outlet
openings automatically to a position of a backrest of one of the
seats. As a result, both the comfort can be further increased and
resource-efficient use of a humidified air stream can be
achieved.
The device for increasing the air humidity can comprise in
particular heating means for heating the supplied air stream, the
enriched air stream or the supplied water. Interaction of a
plurality of heating means for heating one or more of the
aforementioned phases is also conceivable. As a result, besides the
increased air humidity, a high degree of thermal comfort for
persons on board can be ensured. In addition, it is conceivable to
use heating means to kill germs in the water, in order to prevent a
risk of infection.
By using sensor means, one or a combination of the variables
temperature, air humidity, flow rate, pressure and oxygen content
can be detected and optionally displayed by display instruments. In
particular, the supplied air stream, the enriched air stream, an
air stream at one of the outlet openings, supplied water or air in
a surrounding area accessible to one of the seats by convection can
be metrologically detected.
A first control unit can be designed to compare at least one
detected variable with at least one preset variable. In the event
of a deviation, the first control unit can counteract the deviation
by regulating at least one of the humidifying units and/or by
regulating the heating means. In this case, it is conceivable to
arrange the control unit in spatial association with the
humidifying unit concerned. In particular, the first control unit
can be integrated in at least a partial number of the seats.
Furthermore, input means for inputting the at least one preset
variable can be mounted on at least a partial number of the
seats.
Furthermore, the first control unit can be configured for data
communication with a separate second control unit. The second
control unit can serve for controlling air conditioning means for
air conditioning supply air blown into the cabin region, this air
constituting a separate air supply from the enriched air streams.
The first control unit can be designed to transmit the at least one
detected variable and/or the at least one preset variable to the
second control unit.
Additionally or alternatively, through the data communication the
first control unit can receive from the second control unit
measured and/or desired values concerning the air conditioning of
the supply air. Furthermore, the first control unit can correct the
at least one preset variable in dependence on the values received
from the second control unit. For example, the at least one preset
variable for the first control unit can be matched to the second
control unit. It is thereby possible to prevent, for example,
separate air conditioning means from working against one another
due to deviating presettings with regard to temperature and/or air
humidity. The matching can be effected dynamically, i.e. a reaction
of the first control unit is more pronounced for greater deviations
than for small ones.
It is also conceivable for the second control unit on the basis of
the transmitted at least one detected and/or preset variable to
correct its desired value. The said corrections can advantageously
result in the increase of the energy efficiency.
An evaporating section can be provided downstream of the
humidifying unit. The evaporating section can have an S geometry,
heating means, mixing fittings, swirling surfaces or separating
surfaces, which serve for dissolving or separating any aerosol
particles. As a result of the reduction of aerosol particles in the
expelled air, the flying comfort can be further improved or germ
formation prevented.
The gaseous water can be delivered in at least some of the
humidifying units through the following: a membrane module,
preferably a hollow-fiber membrane module; a pad evaporator; an
evaporator electrically heated by trim air or bleed air, preferably
having an evaporator plate; and an ultrasonic evaporator. As a
result of operating temperatures markedly below the boiling point,
for example in the range of 20-40.degree. C., a membrane module can
advantageously be used to eliminate a risk of scalding. Generally,
from the point of view of safety, humidifying means with a lower
temperature in the supplied air stream of the humidifying unit are
advantageous. For example, humidifying means which supply a heat,
corresponding to an evaporation enthalpy, to the water rather than
to an air stream. As a result of the higher operating temperature,
the use of a pad evaporator or a heated evaporator can be
advantageously utilized for killing germs. An ultrasonic evaporator
can be used to achieve a higher energy efficiency and given
appropriate frequency selectioncan have a germicidal effect.
The device for increasing the air humidity can furthermore have an
oxygen source and an inlet opening, arranged downstream of at least
some of the humidifying units. Oxygen or oxygen-enriched air from
the oxygen source can be blown into the supplied air stream through
the inlet opening. As a result, the oxygen partial pressure, which
in flight corresponds typically to a geostatic altitude of about
2000 m, can be increased, for example until an oxygen partial
pressure corresponding to sea level is reached. This can improve
the well-being, in particular, of persons with a reduced capacity
for oxygen uptake. In addition, efficient use of the oxygen source
can take place owing to the targeted air supply.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of a device for increasing the air
humidity are explained in more detail in the following description
of embodiments for the purpose of illustrating and without
restricting the inventive idea. In the figures:
FIG. 1 shows a schematic plan view of a seat arrangement in the
"first class" of an aircraft with two embodiments of a device for
increasing the air humidity; and
FIG. 2 shows a more detailed schematic representation, limited to
one seat, of a further embodiment of a device for increasing the
air humidity.
DETAILED DESCRIPTION
FIG. 1 shows a cabin section, generally designated 10, which is
configured as "first class" in an aircraft. In the example shown,
the cabin section 10 has two rows of seats. For the first row of
seats, a first embodiment 12 of the device for increasing the air
humidity is shown. An alternative embodiment 14 is realized for the
second row of seats. The seats 16 of the first row are assigned in
each case a local water source 18. Mounted within hand's reach of
each seat is a display and input instrument 20 which is connected
to a local control unit 22. In the illustrated exemplary
embodiments 12 and 14, the display and input instrument 20 is
combined with the control unit 22 in an integrated control unit 24.
In addition, a humidifying unit 26 is integrated in the seats 16.
While the seats 28 of the second row also have an integrated
humidifying unit 26, the supply thereof is combined by a central
water source 18 for the entire second row 14.
While the humidifying units 26 and local controls 22 are provided
for local and individual air conditioning, a global air
conditioning system (not shown) is still available for air
conditioning of the entire cabin section 10. Through this system, a
separate supply air stream is blown in along the side walls 30. A
zone control unit 32 is provided for regulating the global air
conditioning system of the cabin section 10. The zone control unit
32 is connected to temperature and air humidity sensors (not shown)
for detecting average atmospheric environment variables in the
cabin section 10.
The water sources 18 are dimensioned for a water consumption
arising due to the humidifying units 26 during a long-distance
flight. Calculations show that, for a long-distance flight (of
approximately 15 hours), the individual water sources 18 on the
seats 16 of the first row 12 should have a capacity of three
liters. The central water source 18 of the second row of seats 14
has a corresponding multiple capacity. The actual water demand also
varies depending on a basic humidity in the cabin region 10.
FIG. 2 shows a schematic representation of individual components
which can be fully or partially realised or combined for various
further embodiments.
In one embodiment, which corresponds to the first row of seats 12,
the local water source 18 shown in FIG. 2 is mounted on the seat
16. In the case of the second row of seats 14, the water is
delivered to the seat 28 by the external water source marked by
reference numeral 34. The water is delivered to the humidifying
unit 26 by a pressure difference in the external water source 34,
by the gravitational force of an overhead-located local water
source 18 or by a pump 36.
Depending on the humidifying unit used, the water can be
continuously or discontinuously metered using the pump 36 and the
valves 38, 40 or 42. By closing the valve 48, with the valves 44
and 46 open, a circulating operation is also possible in which the
pump 36 continuously delivers water through the humidifying unit
26, where appropriate also through the local water source 18. That
is to say the water circulates. For pressure equalisation, the
local water source 18 is connected via lines 52 to the air line 54
and the humidifying unit 26.
A conditioning component 56 is arranged upstream of the humidifying
system 26 for the treatment of the supplied water. In a simple
embodiment, a filter is inserted in the conditioning component 56
(labeled "CC" in FIG. 2 also). In a further embodiment, the
conditioning component 56 comprises an ion exchanger or membranes
for reverse osmosis, which serve for the softening of the water.
For disinfection of certain components of the humidifying system,
disinfectants, for example silver ions for disinfection of air
lines and aerosol filters, are contained in the conditioning
component 56. In a comprehensive embodiment, the conditioning
component 56 has a light source in the ultraviolet spectral region,
which is directed at the water flowing through to kill any
pathogens contained therein. Finally, the conditioning unit 56 has
a mount (not shown) for accommodating smaller vessels with
aromatizing substances which are added to the water flowing
past.
The local water source 18 comprises a holder 58 with a coupling 60
located at the bottom thereof. A water tank 62 with an outlet
opening engages in the coupling 60 when the water tank 62 is
inserted into the holder 58. The coupling 60 allows a quick change
of the water tank 62 prior to a flight. The outlet opening of the
water tank has a closure element (not shown) which by insertion
into the coupling 60 is automatically moved to an open position and
closes again automatically upon removal. The water tank 62 has a
window 64, through which the level can be read. In a further
embodiment, a float is integrated in the water tank as the level
meter 64, the level of the float being detected mechanically or
inductively and displayed by a display instrument (not shown)
accessible to the flight attendants.
A preferred embodiment of the water tank contains sterile water and
is hermetically sealed by a seal at the outlet opening, the seal
being broken open by the coupling piece 60 during insertion of the
water tank 62 into the holder 58. An alternative embodiment has an
opening 66 for filling up the water tank 62.
Salts dissolved in the water reduce an evaporation rate. Therefore,
demineralised water should be used. This also avoids concentration,
which would necessitate a regular cleaning operation in which up to
30% of the water would have to be discarded depending on the
process. This would also require drainage, which in turn could make
necessary a connection to an on-board drainage system. For this
reason too, demineralised water should be used for the benefit of
modularity and to reduce maintenance expenditure.
By opening the valve 40 and closing the valve 38, the water tank 62
can also be filled by the external water source 34, for example a
fresh water system of the aircraft, in the state when installed in
the holder 58.
The external water source 34 can, as shown in the exemplary
embodiment of the second row 14 in FIG. 1, be fed by a common
source 18. Alternatively, a connection to the aforementioned fresh
water system of the aircraft is realised. It is furthermore
advantageous, in the case of an on-board hydrogen fuel cell for
generating electrical energy, for water arising during the power
generation to be used as an external water source 34. Finally, a
condensate which condenses on a separator (not shown) from the
cabin air, is another external source 34 for the humidifying
system.
A drain 68 is provided to discharge waste water or excess water
from the humidifying system. Excess water is emptied from the water
tank 62 through the drain 68 by opening the valve 46.
Correspondingly, by opening the valve 48 with the valves 38 and 42
closed, water is also discharged from the conditioning component
56, for example for drying and sterilizing the conditioning
component 56. Waste water from the humidifying unit 26 can likewise
be discharged through the open valve 44.
In an alternative embodiment, a collecting receptacle 70, as shown
in FIG. 2, is mounted on the cabin floor to perform a drainage
function in the open state of a valve 72. A collecting tank 74
encompasses the collecting receptacle 70 in order to receive water
escaping in the event of an overflow of the collecting receptacle
70, a malfunction or a leak of the humidifying system. To retain
the water, at least the collecting receptacle 70 is equipped with
an absorbent material.
In a first exemplary embodiment, the air stream to be humidified is
provided by a separate aircraft air conditioning system, shown
symbolically in FIG. 2 by reference numeral 76. In an alternative
embodiment, a blower 78 is mounted on the seat 16 and 28 to deliver
cabin air into the humidifying system through an intake opening
80.
An air filter 82 (labeled "AF" in FIG. 2) cleans suspended
particles from the air flowing into the local humidifying unit to
prevent soiling of the humidifying system and therefore reduce both
the maintenance expenditure and the risk of microbial contamination
of the humidifying system. The air filter 82 is preferably a HEPA
filter (High Efficiency Particulate Air filter) for filtering
suspended matter. Condensed water which may arise on the air side
of the humidifying system is led through drainage holes 84 into the
collecting tank 74.
FIG. 2 shows an inlet opening 86, through which oxygen or
oxygen-enriched air from an oxygen source 90 is blown into the
supplied air stream with the valve 88 open. This increases the
oxygen content of the locally blown-in air in the breathing region
of passengers to increase comfort or, preferably, for medical
reasons. For example, an oxygen concentration is set which
corresponds in the breathing region to the oxygen concentration at
sea level. The inlet opening 86 is advantageously arranged upstream
of the humidifying unit 26, since admixing downstream of the
humidifying unit 26 would affect the relative air humidity of the
humidified air stream. Preferably, the inlet opening 86 is provided
with a connection which is compatible with standardised medical
connections for oxygen.
According to a further embodiment, a seat with the aforementioned
oxygen enrichment is specifically designed for transporting sick
persons and has not only an oxygen connection but also standardised
connections for power supply of medical equipment.
For the schematically shown oxygen source 90 in FIG. 2, pressure
vessels, or preferably for avoidance of the hazard potential of a
pressure vessel, chemical oxygen generators are used. In a further
embodiment, which comprises a system for fuel tank inerting,
oxygen-enriched air arising during the production of a protective
gas introduced into the tank is used as the source 90.
An exchangeable or variable restrictor 92, as shown in FIG. 2, is
inserted in the cross-section of an incoming air line. The amount
of air required for local humidification depends on the air flows
in the cabin and therefore varies for different seat positions in
the cabin. By means of the restrictor 92, the air stream is adapted
to the seat position in the cabin. In an extended embodiment, the
variable restrictor is controlled in dependence on an oxygen
partial pressure, for example by the local control 22, since this
pressure varies with flight altitude and the number of passengers.
Here, the control 22 takes account of maximum values for the oxygen
concentration, so that fire-provoking oxygen concentrations are
excluded,
Regardless of the detailed design of the humidifying system 26, for
enrichment of the supplied air with gaseous water the evaporation
enthalpy necessary for the evaporation of liquid water must be
produced. The schematically represented embodiment in FIG. 2
provides, for this purpose, a heater 94 in the incoming air stream,
a heater 96 in the outgoing air stream and a heater 98 in the water
intake. In an alternative exemplary embodiment, the heater is
mounted on the water reservoir 18 instead of on the water intake.
As will be gathered from the following explanations of the
humidifying unit 26, simplified embodiments dispense with
individual heaters.
The air stream supplied to the humidifying unit 26 is detected with
regard to its flow rate by the flow sensor 100, and with regard to
its temperature by the temperature sensor 102. Similarly, flow rate
and temperature of the water intake are detected before the
humidifying unit 26 by the sensors 104 and 106. Two other
temperature sensors 108 and 110 are mounted before and after the
outgoing air stream heater 96, respectively. Finally, a temperature
sensor 112 is arranged in a target TR region of the local
humidification, to detect the local temperature in the region of
the seat 16 or 28. Exemplary target regions TR around a seat 16, 28
are shown in phantom in FIGS. 1 and 2. Downstream of the
humidifying unit 26 there are furthermore provided an air flow
sensor 114 and an air humidity sensor 116 for determining the
relative air humidity. Some of the signals of the sensors 100 to
116 are passed through appropriate cabling to the local control
unit 22. Some of the temperature and flow sensors do not serve for
continuous regulation but to block the operation of heaters and
humidifying units if there is not a sufficient flow. Water
accumulation and overheating is thus precluded. The local
temperature 112 is detected in order to set the air temperature of
the humidified air 110 appropriately and to ensure that it does not
fall below the dew point. Corresponding saturation curves are
tabulated for this purpose in the control unit 22.
In an alternative embodiment, control functions for the operation
of the humidifying unit 26 are performed by a humidification
control (not shown) integrated in the humidifying unit 26. In a
reduced embodiment, individual flow sensors are dispensed with by
mounting and pre-adjusting adjustable restrictors in the
cross-sections.
The humidified air passes through a separator 118 which retains the
liquid water (especially perceptible droplet sizes, including water
vapour). This ensures that finally only the humidified air escapes
into the cabin region through an outlet opening 120. Before the
outlet opening 120, a closure element 122 manually actuable by the
passenger is furthermore mounted, so that the air outlet can be
completely closed if desired. For comfort reasons, preferably an
outlet geometry of the outlet opening 120 is chosen which produces
the low air flow velocities and low turbulence.
By means of a joint 124, the outlet opening 122 can be manually
oriented by the passenger. In a further embodiment, the position of
the outlet opening is furthermore mounted movably along a rail (not
shown) in a ceiling covering located above the seat 16 or 28. In a
further embodiment, electromechanical or hydraulic actuating
mechanisms are provided which act on the joint 124 to automatically
adjust the orientation of the outlet opening 120 to a position of
the backrest of the seat 16 or 28. The adjustment is achieved via a
mechanical or hydraulic coupling or an electronic control (not
shown). In the aforementioned embodiment, which provides for
positioning of the outlet opening 120 along the rail, the actuating
mechanisms for adjusting the positioning of the outlet opening 120
are installed along the rail behind the ceiling covering.
The central element of the humidifying system shown in FIG. 2 is
the humidifying unit 26. As stated above, the humidifying unit 26
is supplied with liquid water and an air stream to be humidified.
Preferably, the humidifying unit 26 is provided with a liquid
sensor which collects information about an amount of water in the
humidifying unit 26 and sends it to the local control unit 22.
Because of the importance of the humidifying unit 26 to the
humidifying system, five embodiments of the humidifying unit 26
will be explained below in more detail.
According to a first embodiment, a membrane module with membranes
made of a material impermeable to liquid water, but permeable to
gaseous water is provided in the humidifying unit 26. The membrane
module has a plurality of membrane fibres which are hollow, so that
the supplied, liquid water can flow through the fibres in the
longitudinal direction. The interior of the hollow-fibre membranes
defines a first volume and the exterior of the hollow-fibre
membranes defines a second volume of the membrane module. In the
membrane module, the hollow-fibre membranes are enclosed
substantially in parallel and without prestress in the second
volume. For an illustration, reference is made to the (single)
figure of U.S. Pat. No. 4,098,852. As a result of the flow through
the hollow-fibre membranes, they extend substantially along their
longitudinal direction. Since the hollow-fibre membranes are firmly
enclosed at their ends in the second volume, owing to the extension
a slight curvature of the hollow-fibre membranes within the second
volume occurs, without thereby their function being impaired. In a
subsequent, dried state, the hollow-fibre membranes reversibly
return to the original state, with the result that at no time are
mechanical stresses transmitted to the membrane module. This has a
beneficial effect on the service life, especially in relation to
sheet membrane modules.
The hollow-fibre membranes separate, with their cylindrical walls,
the first and second volume, so that a mass transfer from one into
the other is possible only through the fine-porous membrane
material. In the above-described embodiment, a portion of the water
flowing through the hollow fibres diffuses from the first volume
into the second volume. As a result, a water-enriched air phase is
obtained in the second volume. In a second preferred embodiment of
the hollow-fibre membrane module, the second, outer volume of the
membrane module is filled with water, while the air to be
humidified flows through the first, inner volume of the
hollow-fibre membranes axially.
The membrane humidifier can either be operated such that
substantially only the amount of water transferred by the phase
transition into the air to be enriched is replaced (so-called
"dead-end" method), or by the pump 36 pumping water in a
circulating manner through the hollow-fibre membranes (so-called
"cross-flow" method). With the latter variant, longer service lives
of the membrane and better humidification performance can be
achieved. One reason for this is that the water flowing past the
membrane walls prevents a deposition of suspended particles, and
thus a rapid blocking of the porous membrane wall.
Advantageously the selective mass transfer of the water through the
membrane also prevents microorganisms, dissolved solids or other
impurities in the water from passing into the air stream. Fouling
of the hollow-fibre membrane surfaces with microorganisms is
achieved by completely drying the membrane, preferably towards the
end of the flight.
The evaporation rate of the humidifying unit with hollow-fiber
membranes depends on the temperatures of the supplied water and the
air stream, and also the pressure difference between the liquid
water and the air phase. As long as the air temperature does not
fall below the water temperature, only gaseous water in the
membrane module will get into the air. Complex regulation which
matches, as a function of the desired relative air humidity, the
amount of water converted to the flow rate of the air stream to be
humidified can therefore be omitted in a simplified embodiment.
Owing to the hollow-fiber membranes, the number of aerosol
particles in the humidified air stream is already so low that an
integrated evaporation section 126 shown in (labeled "IES" in FIG.
2) and an external evaporation section 128 (labeled "EES" in FIG.
2) downstream of the humidifying unit 26 can be dispensed with.
A remarkable advantage of the membrane module is its low operating
temperature. As previously mentioned in connection with the
heaters, the evaporation enthalpy .DELTA.H must be produced
proportionally to the amount of water converted into the gas phase.
This corresponds to a temperature change .DELTA.T=.DELTA.H/C, where
C is the heat capacity of that phase from which the evaporation
enthalpy is withdrawn. In the case of the membrane module, this is
the heat capacity of the liquid water C=C.sub.water, preferably
circulating in the "cross-flow" method. In contrast, in a
humidifying unit operated by heated air, C=C.sub.air is the heat
capacity of the air. Since C.sub.air<<C.sub.water, the
temperature change .DELTA.T.sub.water of the water is considerably
less than that of the air:
.DELTA.T.sub.air>>.DELTA.T.sub.water. In fact, with
recirculation ("cross-flow" method), a heating of the water by only
.DELTA.T.sub.water=3.degree. C. is sufficient. Accordingly, the
operating temperature of the membrane module is also between
20.degree. and 70.degree. C., preferably only between 20.degree.
and 40.degree. C. The actual temperatures depend greatly on an
input and output humidity. An additional factor is the flow rate of
the water in recirculating systems. By comparison, estimates show,
on realistic assumptions for a humidifying system based on air
preheating, an air temperature of approximately 70.degree. C.
A second embodiment of the humidifying unit 26 uses an evaporator
in which a reserve of water is heated above the boiling point and
the resulting water vapour is introduced into the air stream to be
humidified. The evaporator tank has a volume which is heated
electrically or by heat transfer from bleed air or trim air. The
supplied liquid water is introduced into this evaporation tank. To
achieve an even distribution of the vapour in the air to be
humidified, the water vapour is mixed by a nozzle with the dry
incoming air. The evaporator is regulated so that condensation by
supersaturation of the air stream to be humidified does not occur.
As a result, an evaporation section can be dispensed with.
The use of the evaporator prevents microorganisms, dissolved solids
or other impurities in the water from getting into the humidified
air stream. Since the water is supplied to the air stream already
in gaseous form, no evaporation section is required. Moreover, in a
simplified embodiment, an additional heating of the humidified air
stream by the heater 96 can be dispensed with. This allows a
space-saving overall system.
A third embodiment of the humidifying unit 26 comprises an
evaporator plate, with the supplied liquid water being dripped onto
the heated surface of the evaporator plate and evaporated there in
order to be supplied in the gaseous state to the air stream to be
humidified. The evaporator plate is preferably electrically heated,
in alternative embodiments by bleed air or trim air.
Analogously to the aforementioned embodiment of an evaporator, the
gas phase of the water provided by the evaporator plate is mixed by
a nozzle with the dry air. The aforementioned advantages with
regard to the killing of microorganisms and the retention of other
impurities in the water as previously mentioned for the evaporator
also apply to the embodiment with an evaporator plate. In addition,
an evaporation section and a heating of the humidified air stream
can also be dispensed with, resulting in a space-saving overall
system.
A fourth embodiment of the humidifying unit 26 uses a pad
evaporator. Such a pad is provided, for example, by a sponge-like
silicate fibre structure. Into this is led the air which is to be
humidified and which is preheated by means of the heater 94 to
approximately 70 to 80.degree. C. The air flows through the fibrous
pad, in which the supplied water adheres by capillary action to the
entire surface of the fibres over a large area in order to
effectively pass into the flow-through air as gaseous water.
A fifth embodiment of the humidifying unit 26 provides for
introducing water-containing aerosol produced via an ultrasonic
bath, together with the supplied air, into an integrated
evaporation section 126. By appropriate mixing fittings in the
evaporation section, turbulence of the aerosol with the supplied
air occurs, with the result that the evaporation enthalpy necessary
for the evaporation of the aqueous aerosol particles is withdrawn
from the supplied air. Any aerosol particles remaining are removed
from the humidified air stream by the droplet separator 118. The
separator 118 is preferably designed so that separated water is
retained in it in order, in time, nevertheless to evaporate in the
humidified air stream. This is efficient and saves a water
drain.
In addition to the aforementioned embodiments of the humidifying
unit 26, other humidifying devices already known to a person
skilled in the art may be realised in the humidifying unit 26.
To regulate the individual components of the humidifying system
which have been explained, the local control unit 22 is employed.
The local control unit 22 receives the aforementioned signals of
the sensors 100 to 116, and furthermore controls the power of the
blower 78, of the heaters 94, 96 and 98, and also of the
humidifying unit 26 and of the pump 36. For this purpose, a local
temperature and a local air humidity are determined by the local
control unit from the detected variables of the sensors and are
displayed on the display and input instrument 20 connected to the
local control unit 26 to be retrievable by the passenger. In a
simple embodiment, the display and input instrument 20 has rotary
knobs in order to preset a desired temperature or relative air
humidity. In a preferred embodiment of the display and input
instrument 20, the input is provided by a touch screen (not shown)
with corresponding graphically represented input options. Here, the
input option is a menu item of the in-flight entertainment system.
The preset temperature and relative air humidity are compared by
the local control unit 22 with the corresponding detected
variables. In the event of deviations which exceed a preset
regulating range, the controlled components are regulated so that
they counteract the deviations.
A further advantage results from a combined regulation of
temperature and air humidity by the local control unit 22 with the
proviso of an individual temperature control of the air. The
temperature preset on the display and input instrument 20 is
regulated while taking account of the evaporation enthalpy
withdrawn by the evaporation. For example, to improve energy
efficiency, use is made of the fact that cooler air is provided in
the course of the humidification of the air. At the same time, the
comfort of the persons for whom the global temperature setting is
not pleasant is further increased.
In addition, the local control unit 22 is connected to the zone
control unit 32 for data communication. By means of the data
communication, the local control units marked with reference
numeral 24 in FIG. 1 transmit the detected local temperature
together with the preset temperature to the zone control unit 32.
The latter calculates, from the received detected and preset
variables, average values for the entire cabin region 10. The
average values are used by the zone control unit 32 as measured or
desired values for control of the separate global air conditioning
system of the cabin region 10. By this data communication, the
energy consumption for air conditioning of the cabin region 10 is
advantageously optimised while maintaining the individual
regulability.
Via another global display and input device (not shown) which is
accessible to a cabin crew, global presettings for the individual
seats, especially the local air humidity, can be provided. This is
useful since the local air humidity is perceived by some passengers
not as sufficiently clearly as would be necessary for independent
regulation. In a simplified embodiment, the local display and input
instrument 20 may be limited to a choice of temperature, while the
local air humidity is chosen by the cabin crew on the global
display and input instrument. For a given local temperature, the
humidifying unit is then typically controlled so that a relative
air humidity between 90 and 100% is achieved at the outlet opening
120.
For adjustment of the outlet openings 120 of the whole system
(outside of the regular operation), the closure 122 can also be
removed without tools. This results in an opening through which
visualisation means, for example the mist of a mist generator, can
be introduced. This allows the outflow behaviour behind the outlet
opening 120 to be visualised. For adjustment, an adjusting program
in the local control unit 22 can be called that passes through
different temperature ranges. As a result, the adjustment can also
take account of deviations in the outflow behaviour due to thermal
convection or density differences between cabin air and air stream.
Finally, through the mist visualisation it is possible in a simple
manner to adjust the joint 124 or the actuating mechanism acting on
the joint 124 and the associated control with regard to the
position of the seat 16 or 28.
Another advantage of the described local humidifying system 12 with
the water tank 62 and blower 78 integrated in the seat 16 is its
modular construction. The humidifying system is thus easily
retrofitted in existing aircraft, for example by replacing
individual seats. Moreover, the configuration flexibility of the
cabin is not limited by the modular and integrated
construction.
* * * * *